Rhinolithodes wosnessenskii Brandt (1849)

Common name(s): Rhinoceros crab

Rhinolithodes wosnessenskii approx 7 cm across carapace, captured
by SCUBA off Sares Head August 2004 See below for more photos.

Photo by: Dave Cowles August 2004

Description: This lithodid crab has a
carapace with a triangular outline and a very deep semicircular depression
on the dorsal side. The claws and legs are covered with spines and
even longer hairlike setae. (picture)
The (antero)lateral margins of the carapace have sharp-tipped spines (picture).
The rostrum has one small point like a small rhinoceros horn (picture),
leading to the name. Color is usually yellowish-brown with orange
and white.

How to Distinguish from Similar Species: The
only other local Lithodid crab with a triangular carapace is Phyllolithodes
papillosus (the heart crab). It differs from that species in
that P. papillosus has fewer, stiff blunt spines on the legs and
few hairlike setae on the legs, has a rostrum of two blunt lobes, and the
dorsal concavity of the rostrum is more strongly divided into a left and
a right depression bordered by large tubercles.

Geographical Range: Kodiak, Alaska
to Crescent City, CA

Depth Range: 6-73 m

Habitat: Rock or gravel bottoms, often
hiding in crevices.

Biology/Natural History: Not often
found in most areas of Puget Sound/Straits (though this species is often
found on Sares Head). Slow-moving. Interestingly, even the
back of the eyestalks have small spines (picture)

References:

Dichotomous Keys:

General Notes and Observations: Locations, abundances,
unusual behaviors, etc.:The anterior margin of the carapace is covered with sharp spines (see
at the base of the hairy legs)
The rostrum has a single hornlike spine, visible from the side
The abdomen is held tightly against the underside of the thorax.
The chelipeds are covered with hairlike setae, as are the rest of the legs.
Authors and Editors of Page:Dave Cowles (2004): Created original page